Block copolymers prepared by reacting prepolymers containing terminal isocyanate groups with aromatic oligamides

ABSTRACT

BLOCK POLYMER OF (1) A PREPOLYMER HAVING TERMINAL ISOCYANATE GROUPS OBTAINED BY REACTING A DIFUNCTIONAL COMPOUND HAVING ACTIVE HYDROGEN ATOMS AND AN AVERAGE POUND AND (2)F AN AROMATIC OLIGOMIDE HAVING TERMINA AMINO GROUPS, AN AVERAGE MOLECULAR WEIGHT OF 300-5000 AND A MELTING POINT NOT LOWER THAN 100*C., HAS HIGH ELASTIC PERFORMANCE OVER A WIDE RANGE OF TEMPERATURE, SUCH PERFORMANCE BEING STABLE AGAINST TEMPERTAURE VARIATION, AND IS USEFUL IN MAKING FIBERS, FILMS, ETC., AS COATING MATERIAL, ADHESIVE MATERIAL ETC., AND AS BLEND WITH OTHER ELASTOMER, ETC. TO IMPROVE PROPERTIES OF THE LATER. THE BLOCK POLYMER IS PRODUCED BY REACTING A DIFUNCTIONAL COMPOUND HAVING ACTIVE HYDROGEN ATOMS AND AN AVERAGE MOLECULAR WEIGHT OF 500-20,000 WITH AND EXCESS OF A DIISOCYANTE COMPOUND TO PREPARE A PREPOLYMER HAVING TERMINAL ISOCYANATE GROUPS, AND REACTING THE FORMED PREPOLYMER WITH AN AROMATIC OLIGOAMIDE HAVING TERMINAL AMINO GROUP, AN AVERAGE MOLECULAR WEIGHT OF 300-5000 AND A MELTING POINT NOT LOWER THAN 100*C.

United States Patent US. Cl. 260-18 TN 12 Claims ABSTRACT OF THE DISCLOSURE Block polymer of (l) a prepolymer having terminal isocyanate groups obtained by reacting a difunctional compound having active hydrogen atoms and an average molecular weight of 50020,000 with a diisocyanate compound and (2) an aromatic oligoamide having termina amino groups, an average molecular weight of 3005000 and a melting point not lower than 100 C., has high elastic performance over a wide range of temperature, such performance being stable against temperature variation, and is useful in making fibers, films, etc., as coating material, adhesive material, etc., and as blend with other elastomer, etc. to improve properties of the latter. The block polymer is produced by reacting a difunctional compound having active hydrogen atoms and an average molecular weight of SOD-20,000 with an excess of a diisocyanate compound to prepare a prepolymer having terminal isocyanate groups, and reacting the formed prepolymer with an aromatic oligoamide having terminal amino groups, an average molecular weight of 3005000 and a melting point not lower than 100 C.

This invention relates to novel elastomeric block copolymers and to the production thereof. More particularly this invention relates to elastomeric block copolymers of a prepolymer having terminal isocyanate groups and an aromatic oligoamide having terminal amino groups, and also to the production thereof.

It is known to produce the so-called polyurethane elastomer by preparing a prepolymer having terminal isocyanate groups and then subjecting the prepolymer to chain extending reaction with a diamine which is nonaromatic and/or low molecular weight liquid. However, these conventional polyurethane elastomers have some drawbacks. Thus, for example, they are not fully satisfactory in thermal stability (the elastic performance is considerably affected by temperature variation).

Therefore, it is an object of this invention to provide a novel and improved urethane block copolymer which has a high elastic performance.

It is another object of this invention to provide a novel and improved urethane block copolymer which shows a high elastic performance over a wide range of temperature.

It is still another object of this invention to provide a novel and improved urethane block copolymer, the. excellent elastic performance of which is stable against temperature variation.

Other objects, features and advantages of the invention will be apparent from the following description.

Briefly, the novel block copolymer of this invention is a block copolymer of (1) a prepolymer having terminal isocyanate groups obtained by reacting a difunctional compound having active hydrogen atoms and an average molecular weight of SOD-20,000 with a diisocyanate com- "ice pound and (2) an aromatic oligoamide having terminal amino groups, an average molecular weight of 300-5000 and a melting point not lower than C.

According to this invention these novel block copolymers are produced by reacting a difunctional compound having active hydrogen atoms and an average molecular weight of SOD-20,000 with a diisocyanate compound to prepare a prepolymer having terminal isocyanate groups, and reacting the formed prepolymer with an aromatic oligoamide having terminal amino groups, an average molecular weight of 3005000 and a melting point not lower than 100 C.

The present invention will be explained in more detail as follows.

The method of this invention comprises two steps, i.e. the first step for preparing a prepolymer having terminal isocyanate groups and the second step for block copolymerizing the prepolymer with an aromatic oligoamide having terminal amino groups.

The first step is well known per se in the art of the production linear polyurethane elastomers.

The difunctional compounds to be used in the first step of the method of this invention are those having active hydrogen atoms and having an average molecular weight of 500-20000 and preferably a glass transition temperature not higher than 10 C. More preferably, the difunctional compounds have. an average molecular weight of 100010,000 and a glass transition temperature not higher than 30 C.

Examples of these difunctional compounds are aliphatic polyether diols, aliphatic polyester diols, dihydroxy polyhydrocarbons, etc. More particular and preferable examples of these diols are polyoxytetrarnethylene glycols, poly-e-caprolactone diols, polyoxypropylene glycols, polybutadiene diols, polybutylene glycols, polyamylene glycols, etc. Other diols such as polyalkylene ether thioether glycols, alkylenearyl ether glycols, etc. conventionally used in the art of linear polyurethane elastomers may also be employed in this invention. A mixture of these compounds may also be used.

Diisocyanate compounds also well known in the art of the production of linear polyurethane elastomers may be used in carrying out the method of this invention. Examples of these diisocyanates are 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, halogen-substituted or non-substituted diphenylmethane diisocyanate, xylylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 4,4'-biphenylene diisocyanate, methylene-bis-(4-phenyl diisocyanate), octamethylene diisocyanate, w,w'-dipropyl diisocyanate, cyclohexan1,3 diisocyanate, cyclohexaue-1,4-diisocyanate, 2,2,-6,6' tetraethylene 4,4 diphenylmethane diisocyanate, dibenzyl diisocyanate, diphenylsulfon-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-diphenyl diisocyanate, etc. Other diisocyanate compounds known in the art of the production of polyurethane elastomers may also be used in this invention.

The difunctional compound is reacted with an excess of the organic diisocyanate compound. Preferably about 2 equivalents of the diisocyanate are employed with respect to the difunctional compound.

The reaction may be conducted in the presence or absence of a catalyst and in the presence or absence of a solvent. Examples of the catalyst when used are amines such as triethylamine, and organo-metallic compounds such as cobalt naphthenate, tin chloride, tetra-n butyl tin, etc. Examples of the solvent when used are tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, toluene, anisol, etc. These and other catalysts and solvents are also Well known in the art of the production of linear polyurethane elastomers.

of moisture. Thus, it is preferable to carry out the reac- T tion in a dry air or in a dry inert atmosphere such H2N C NH 1\H2 as dried nitrogen gas. The reaction temperature is generally 50-150 C., preferably 90-l30 C. and the reac- 3 process of this invention.

tion time is generally 20 minutes to 3 hours, preferably 30-90 minutes. r 0 0 The prepolymer having terminal rsocyanate groups 1s l i NH3 1 I a a L The aromatic oligoamides to be used 1n the second step are those having terminal amino groups, an average These ollgoamldes y e P p 111 val'lous manner molecular Weight of 300-5000, preferably 346-1200, and known P However, It Is Preferable to P p them then copolymerized with an aromatic oligoamide having a melting point not less than 100 C., preferably not less by reacting an aromatic diamine with at least one aromatic Preferably the reaction is conducted in the absence 0 O terminal amino groups. This is the second step of the 10 than 150 C. If the molecular weight and/or melting point dibasic acid halide, the former being used in a mol of h li id to b employed are out f h range excess to the latter. In this case a mixture of amides is specified above the resulting block-copolymer elastomers @mled and such mixture y be used in carrying out the would have no desirable elasticity and/ or thermal stability. Invention Without separating one and l?articular amide- The wholly aromatic oligoamide (wholly aromatic A mixture of two or more of these amides y also diamines of a high molecular weight) having terminal be d, if d sir d. amino groups to be used in this invention may be reprer the copolymerization the amide is used in an sented by the following general formula: amount of 85-110%, preferably about 100% of the theoretical amount in respect of free isocyanate groups presf cut in the prepolymer. Thus, it is recommended to conduct a quantitative analysis for free isocyanate groups Hm X *NHZ present in the prepolymer, in order to determine the J proper amount of the oligoamid'e. R2 R4 11 (I) The block copolymerization may be conducted in the presence or absence of an organic solvent and in the R2 R3 R4 presence or absence of a catalyst.

Examples of the solvents which may be used are N,N- HZN Y X Z 'dimethylformamide, N,N-dimethylacetamide, dirnethyl- L J (ID sulfoxide, hexamethylenesulfonamide, etc. which can dis- 5 solve the resulting block copolymer. wherem each of 3 and R4 15 hydrogen halogefl Among catalysts which may be used in the copolymer- Or an alkyl group havmg carbfm atoms X 15 ization are, for example, stannous chloride, stannic chlo- NRCOr CONR NR 15 hydrogen halo ride, di-n-butyl tin dilaurate, ferrous acetyl acetonate, gen or an alkyl group having 1-4 carbon atoms, and lead oleate, etc. each of Y and Z is Smgle bond connectmg the adlacent 40 Generally, this copolymerization may be conducted at phenylene groups or a divalent group selected from the a temperature of from .0 C. to C" preferably class consisting of O, and 70 C. The reaction is continued until the copolymeri R zation proceeds to a desired extent. Generally, a reaction time of 30 minutes to 24 hours is employed.

1 The formed block copolymer may be recovered in any R" suitable manner. Thus, for example, the polymer soluwherein each of and is hydrogen: halogen an tion is poured into a non-solvent for the polymer. Exalkyl group having Carbon and n is a number amples of such non-solvent are water, alcohols, ketones, of at least 0I1eetc., but water is preferable.

Among these Compounds, those represented by the The novel elastomeric block copolymers of this inven- Fel'mllla I are preferable- Among the Preferred P tion have a glass transition temperature not higher than pounds of the Formula I are for example the following C Preferably not higher than C Compounds: Since the novel block copolymers contain rigid seg- 0 0 ments of aromatic oligoamides of high molecular weight, g g they have various excellent properties not seen in conventional polyurethane elastomers and natural or synthetic rubbers. Thus the elastomers of this invention are stable against temperature variation and retain excellent elastic properties even at a high temperature. They have I NH -G O NH NH|C 0- -NI-I H a high elongation even with a high strength, in contrast to conventional rubbers Which are low in strength when the elongation is high. 3 3 The block-copolymers of this invention may be formed,

I I? "I in a conventional manner, into various shaped articles 1rN1r-- --i )-1IN-- --NHC- --NII1I such as fibers, films, etc. and are also useful as coating material, adhesive material, etc. The block copolymer of ll J this invention may be blended with another elastomer or 1 2 plastic material to improve the properties of the latter.

The following examples illustrate the invention.

EXAMPLE 1 A four-necked flask fitted with a stirrer and nitrogen inlet was charged with 43.5 g. of freshly distilled 2,4- 5 tolylenediisocyanate, and there were added dropwise for minutes 2.5 g. of polyoxytetramethyleneglycol (molecular weight 2010, glass transition temperature 45 C.) in nitrogen atmosphere. Then the mixture was stirred on an oil bath at 120:5 C. for 90 minutes. The resulting prepolymer contained 3.58% of free NCO groups. 74.3 g. of this prepolymer were placed in a dried flask, and a solution of 10.8 g. of N,N'-metaphenylene-bis-meta aminobenzarnide (molecular weight 346, melting point 214 C.) dissolved in 50 ml. of dry dimethylformamide was poured thereinto. The mixture was stirred at the room temperature for 2 hours to obtain a viscous solution. The viscous solution was poured into water and the precipitate formed was separated, washed twice respectively with methanol and acetone, and dried at 70 C. under reduced pressure.

The block copolymer thus obtained was dissolved in dimethylformamide and the solution was spread on a glass plate. Upon removal of the solvent by evaporation 6 A tough, brown, elastic film prepared from this block copolymer in the same manner as in Example 1 had the following properties:

,u =0.33, softening point: 230-260 C. Initial modulus: 71 kg./cm. Stain recovery:

87% (at C.) 84% (at 70 c. Tensile stress at 200% elongation:

145 kg./cm. (25 C.) 137 kg./cm. (70 C.)

Ultimate elongation: 368% Ultimate strength: 417 kg./cm.

EXAMPLE 3 To 66 g. of freshly distilled 1,5-naphthalene diisocyanate in a four-necked flask same as in Example 1 were added dropwise for 15 minutes and in nitrogen atmosphere 324 g. of poly-e-caprolactonediol (molecular weight 2078). The mixture was then stirred for 90 minutes on an oil bath at 100i5 C., to form a prepolymer. After cooling, 90 g. of an oligoamide (molecular weight 594, melting point 284-285 C.) of the formula:

there was obtained a tough, colorless, transparent, elastic film having the following properties:

,u =0.64, softening point: 205230 C. Initial modulus: kg./cm. Strain recovery:

78% (at 25 C.) 70% (at 70 C.) Tensile stress at 200% elongation:

30 kg./cm. (25 C.) 24 kg./cm. (70 C.) Ultimate elongation: 1,100% Ultimate strength: 378 kg./cm.

EXAMPLE 2 In the same four-necked flask as used in Example 1 there were placed 38.8 g. of freshly distilled 2,4-tolylenediisocyanate, and there were added dropwise for 15 minutes 232 g. of polyoxytetramethylene glycol (molecular weight 2078, glass transition temperature C.) in a nitrogen atmosphere. After the addition, the mixture was heated while stirring on an oil bath at 100i5 C. for 90 minutes. The resulting prepolymer contained 3.5% of free NCO groups. 41.9 g. of this prepolymer were placed in a dried flask, and a solution of 10.5 g. of N,N- metaphenylene bis[N,N' metaphenyleneamide(metabenzamide)] (molecular weight 594, melting point 284- 285 C.) of the formula 0 will 1 Hr... ll..-

dissolved in 50 ml. of dry dimethylformamide was poured thereinto. The mixture was stirred at the room temperature for 2 hours to obtain a viscous solution. This solution was processed in the same manner as in Example 1 and there were obtained 41.5 g. of the block-copolymer.

dissolved in 850 cc. of dimethylacetamide were added to the prepolymer, and the mixture was stirred for 12 hours at 60 C. to obtain a viscous solution of a block copolymer.

A tough, yellow, opaque, elastic film prepared from this block copolymer in the same manner as in Example 1 had the following properties:

,u =0.36, softening point: 240-280 C. Initial modulus: 340 kg./cm. Strain recovery: 47.8% (25 C.) Tensile stress at 200% elongation:

53 kg./cm. (25 C.)

EXAMPLE 4 To 110.3 g. of freshly distilled P,P'-diphenyl methane diisocyanate were added dropwise for 15 minutes in nitrogen atmosphere 443.4 g. of polyoxypropyleneglycol (molecular weight 2010, glass transition temperature 70 C.). After the addition the mixture was stirred for 60 minutes on an oil bath at i5 C, to form a prepolymer containing 3.31% of free isocyanate groups. To 39 g. of this prepolymer in a dried flask was poured a solution of 9 g. of the amide same as in Example 3 dissolved in 50 ml. of dry dimethyl-formamide, and the mixture was stirred at the room temperature for 2 hours to obtain a viscous solution of block copolymer.

A brown, transparent, tough, elastic film obtained from this block copolymer in the same manner as in Example 1 had the following properties:

=0.69, softening point: 260-280 C. Initial modulus: 42 kg./cm. Strain recovery:

94.6 kg./cm. (at 25 C.) 92.5 kg./cm. (at 70 C.) Tensile stress at 200% elongation:

30 kg./cm. (25 C.) 29 kg./cm. (70 C.)

7 EXAMPLE To 5.23 g. of p,p'-diphenylmethane diisocyanate in a four-necked flask were added dropwise 10.4 g. of polyoxypropyleneglycol (molecular weight 1000, glass transition temperature 70 C.). After the addition, the mixture was stirred for 90 minutes on an oil bath at 120i5 C. to form a prepolymer containing 5.8% of free NCO groups. To 8.94 g. of this prepolymer in a dried flask was poured a solution of an oligoamide (molecular weight 822, melting point 308310 C.) of the following formula:

t l. l 1.

dissolved in 25 ml. of dry dimethylformamide, and the mixture was stirred for 2 hours at the room temperature to obtain a viscous solution of a block copolymer.

The solution was processed and formed into a film in the same manner as in Example 1. The film was tough, opaque and elastic.

EXAMPLE 6 A 20% solution of the block copolymer of Example 3 dissolved in dimethylformamide was extruded through 6 spinning orifices (each being 0.12 mm. in diameter) into an aqueous coagulating bath of a length of 3 m., and the formed filaments were taken-up at a rate of m./min. The white elastic filaments thus obtained could be stretched 3 times the length.

EXAMPLE 7 Before After test; test Ultimate elongation (percent) 3.0 6.9 Ultimate strength (kg/mm!) 1. 48 2. 7

EXAMPLE 8 A cellulosic paper sheet (4 mils in thickness, a-cellulose content 99%) was impregnated with a solution of the block copolymer of Example 1 and dried. Ten of the dried sheet (resin content 60%) were stacked. The stack was clamped between smooth stainless steel plates and heated in a press at 170 C. under 30 kg./cm. for 4 minutes. There was obtained an elastic laminate sheet.

EXAMPLE 9 The block copolymer of Example 3 was dissolved in dimethylformamide and the solution was coated on a wooden sheet and dried. The dried coating contained the polymer in an amount of 4-5 g./m. The coating was lustrous, wear-resistant and had a soft hand and feel.

EXAMPLE 10 The film obtained in Example 5 was washed with an alkaline aqueous solution containing NaOH and NaCN for 10 seconds and further with water for 30 seconds. Then the film was treated for 3 minutes at the room temperature with a sensitizing solution of SnCl 10 g. and HCl 40 g. dissolved in 1000 cc. water, washed with water, further treated for 5 minutes at the room temperature with an activator solution of PbCl l g. and HCl 10 cc.

dissolved in 4000 cc. water, and washed with water. Then, the film was chemically copper plated in the usual man ner for 15 minutes. Thus, there was deposited a copper layer (about 0.3 in thickness) firmly adhered to the surface of the film.

EXAMPLE 11 A mixture of 20 parts by weight of the block copolymer of Example 2 and 100 parts by weight of polyvinylchloride (molecular weight 1000) Was homogeneously blended on a roll mill (heated to 170 C.) for 5 minutes and formed into an opaque sheet. This sheet was pressheated at 170 C. for 30 seconds to obtain a transparent sheet which is far more excellent in impact strength than the sheet consisting only of the same polyvinylchloride. When the sheet was 3 times at 4050 C. there was obtained an opaque tough sheet.

EXAMPLE 12 A solution of 20 parts by weight of the block copolymer of Example 2 dissolved in dimethyl-formamide and a solution of 100 parts by weight of polyvinylchloride (molecular weight 1000) dissolved in tetrahydrofuran were mixed together and the homogeneous mixture was poured into water to coprecipitate the polymers. The precipitate was separated, washed and dried. The polymer blend thus obtained was processed in the same manner as in Example 11 to form a sheet with an improved impact strength.

EXAMPLE 13 While stirring a mixture of 32 g. m-phenylenediamine, 7.5 g. borax, 10 g. sodium sulfite and 1600 g. water, there Was added a solution of 15 g. isophthaloyl chloride and 5 g. terephthaloyl chloride in 1000 g. xylene. The mixture was further stirred for 2 minutes and the precipitate formed was separated, washed twice with water and once with acetone, and then dried at 150 C. for 1 hour, to obtain 24 g. of gray powder. The product contained about 1.33 mols of the diamine unit per mole of total of isophthalate and isophthalate units, and had an average molecular weight of 822 and a melting point higher than 300 C. The average structural formula of this product was as follows:

0 O H..- LNatOaNHOLM,

EXAMPLE 14 A mixture of 38.8 g. of freshly distilled 2,4-tolylenediisocyanate and 232 g. of p0lyoxytetramethyleneglycol (molecular weight 2078) was stirred at 100 C. for minutes in nitrogen atmosphere. The resulting prepolymer contained 3.5% of NCO groups. The prepolymer 41.9 g. was charged in a dried flask, and 14.4 g. of the product of Example 13 dissolved in g. of dry dimethylacetamide were added thereto. The mixture was stirred at the room temperature for 2 hours to obtain a solution containing 49.0 g. of block copolymer.

The polymer solution was processed and formed into a film in the same manner as in Example 1. The yellow transparent film thus obtained had the following properties:

200% modulus. kg./cm. 85 80 Recovery, percent 80 80 EXAMPLE 15 was obtained a solution of oligoamide having the following average structural formula:

To this solution were added 54.8 g. of the prepolymer prepared in Example 14 to obtain a polymer solution,

from which was formed a transparent yellow elastic film. 1

As explained hereinbefore, the elastomers of this invention have stable elastic properties against temperature variation. This is demonstrated by the following table:

wherein each of R R R and R is a member selected from the group consisting of hydrogen, halogen atoms and alkyl groups having 1-4 carbon atoms, X is NRCO or CONR- wherein NR is a member selected from the group consisting of hydrogen, halogen atoms and alkyl groups having 1-4 carbon atoms, each of Y and Z is a single bond connecting the adjacent phenylene MODULUS Ex. 50 C -30 C. l0 C. 10 C. 50 C. 70 C. 90 0. 110 C. 1 3X10 3x10 2X10" 2X10 7X10 6X10 x10 5X10 1 2 1X10 8X10 5X10 4X10 3. 2X 3X10 3X10 2. 6X10 3 1x10 9x10 3x10 7x108 x 5 A 2. 2X10" 8X10 8X10 5X10 1. 0 X10 6X10 5x10 4 1O B 5X10 1X10 4. 5X10 3. 2X10 2. 2X10 2. 2X10 6X10 8. 2X10 Remarks:

A=Same as Example 2 except that the followmg dlamme was used in place of the oligoamide.

B Same as Example 2 except that; hydrazine was used in place of the oligoamide.

and

groups or a divalent group selected from the class consisting of O, -SO CO- and wherein each of R and R" is a member selected from the class consisting of hydrogen, halogen atoms, or alkyl groups having 1-4 carbon atoms, and n is a number of at least one, and thereafter precipitating the block polymer with water, washing and recovering the thus precipitated polymer.

2. A method as claimed in claim 1 wherein the oligoamide is selected from the group consisting of the compounds of the following formulae:

3. A method as claimed in claim 1 wherein the amide is used in an amount of 85+110% of the theoretical amount in respect of the free isocyanate groups present in the prepolymer.

4. A method as claimed in claim 1 wherein the reaction of the prepolymer with the oligoamide is conducted at a temperature of C. to 120 C.

5. A method as claimed in claim 1 wherein the solvent is selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide and hexamethylenesulfonamide which can dissolve the resulting block copolymer.

6. A method as claimed in claim 1 wherein the reaction of the prepolymer with the oligoamide is conducted in the presence of a catalyst.

7. A method as claimed in claim 6 wherein the catalyst is selected from the group consisting of stannous chloride, stannic chloride, di-n-butyl tin dilaurate, ferrous acetyl acetonate and lead oleate.

8. A block copolymer as prepared by the method of claim 1.

9. A block copolymer prepared by reacting a difunctional compound having active hydrogen atoms and an average molecular weight of 50020,000 with an excess of an organic diisocyanate compound to prepare a prepolymer having terminal isocyanate groups, and reacting the formed prepolymer with an aromatic oligoamide having an average molecular weight of 300-5000 and a melting point not lower than 100 C., said oligoamide being selected from the group consisting of the com pounds of the formulae:

wherein each of R and R is a member selected from the class consisting of hydrogen, halogen atoms or alkyl groups having 1-4 carbon atoms, and n is a number of at least one.

10. A block copolymer according to claim 9 wherein the oligoamide is selected from the group consisting of the compounds of the following formulae:

"l EL NHa Himl HIN and

References Cited UNITED STATES PATENTS 3,245,961 4/ 1966 Fetscher et al 260-77.5 3,375,299 3/1968 Levine et al. 260-830 3,405,162 10/1968 Kuryla 260465.6 3,428,710 2/1969 Daumiller et a1. 260857 DONALD E. CZAI A, Primary Examiner H. S. COCKERAM, Assistant Examiner US. Cl. X.R.

161- 190; 26030.4, 30.8, 32.6, NH, 77.5 AM, 77.5 SP, 78 A, 78 R, 859' The following examples illustrate the invention.

EXAMPLE 1 A four-necked flask fitted with a stirrer and nitrogen inlet was charged with 43.5 g. of freshly distilled 2,4- 5 tolylenediisocyanate, and there were added dropwise for minutes 2.5 g. of polyoxytetramethyleneglycol (molecular weight 2010, glass transition temperature 45 C.) in nitrogen atmosphere. Then the mixture was stirred on an oil bath at 120:5 C. for 90 minutes. The resulting prepolymer contained 3.58% of free NCO groups. 74.3 g. of this prepolymer were placed in a dried flask, and a solution of 10.8 g. of N,N'-metaphenylene-bis-meta aminobenzarnide (molecular weight 346, melting point 214 C.) dissolved in 50 ml. of dry dimethylformamide was poured thereinto. The mixture was stirred at the room temperature for 2 hours to obtain a viscous solution. The viscous solution was poured into water and the precipitate formed was separated, washed twice respectively with methanol and acetone, and dried at 70 C. under reduced pressure.

The block copolymer thus obtained was dissolved in dimethylformamide and the solution was spread on a glass plate. Upon removal of the solvent by evaporation 6 A tough, brown, elastic film prepared from this block copolymer in the same manner as in Example 1 had the following properties:

,u =0.33, softening point: 230-260 C. Initial modulus: 71 kg./cm. Stain recovery:

87% (at C.) 84% (at 70 c. Tensile stress at 200% elongation:

145 kg./cm. (25 C.) 137 kg./cm. (70 C.)

Ultimate elongation: 368% Ultimate strength: 417 kg./cm.

EXAMPLE 3 To 66 g. of freshly distilled 1,5-naphthalene diisocyanate in a four-necked flask same as in Example 1 were added dropwise for 15 minutes and in nitrogen atmosphere 324 g. of poly-e-caprolactonediol (molecular weight 2078). The mixture was then stirred for 90 minutes on an oil bath at 100i5 C., to form a prepolymer. After cooling, 90 g. of an oligoamide (molecular weight 594, melting point 284-285 C.) of the formula:

there was obtained a tough, colorless, transparent, elastic film having the following properties:

,u =0.64, softening point: 205230 C. Initial modulus: kg./cm. Strain recovery:

78% (at 25 C.) 70% (at 70 C.) Tensile stress at 200% elongation:

30 kg./cm. (25 C.) 24 kg./cm. (70 C.) Ultimate elongation: 1,100% Ultimate strength: 378 kg./cm.

EXAMPLE 2 In the same four-necked flask as used in Example 1 there were placed 38.8 g. of freshly distilled 2,4-tolylenediisocyanate, and there were added dropwise for 15 minutes 232 g. of polyoxytetramethylene glycol (molecular weight 2078, glass transition temperature C.) in a nitrogen atmosphere. After the addition, the mixture was heated while stirring on an oil bath at 100i5 C. for 90 minutes. The resulting prepolymer contained 3.5% of free NCO groups. 41.9 g. of this prepolymer were placed in a dried flask, and a solution of 10.5 g. of N,N- metaphenylene bis[N,N' metaphenyleneamide(metabenzamide)] (molecular weight 594, melting point 284- 285 C.) of the formula 0 will 1 Hr... ll..-

dissolved in 50 ml. of dry dimethylformamide was poured thereinto. The mixture was stirred at the room temperature for 2 hours to obtain a viscous solution. This solution was processed in the same manner as in Example 1 and there were obtained 41.5 g. of the block-copolymer.

dissolved in 850 cc. of dimethylacetamide were added to the prepolymer, and the mixture was stirred for 12 hours at 60 C. to obtain a viscous solution of a block copolymer.

A tough, yellow, opaque, elastic film prepared from this block copolymer in the same manner as in Example 1 had the following properties:

,u =0.36, softening point: 240-280 C. Initial modulus: 340 kg./cm. Strain recovery: 47.8% (25 C.) Tensile stress at 200% elongation:

53 kg./cm. (25 C.)

EXAMPLE 4 To 110.3 g. of freshly distilled P,P'-diphenyl methane diisocyanate were added dropwise for 15 minutes in nitrogen atmosphere 443.4 g. of polyoxypropyleneglycol (molecular weight 2010, glass transition temperature 70 C.). After the addition the mixture was stirred for 60 minutes on an oil bath at i5 C, to form a prepolymer containing 3.31% of free isocyanate groups. To 39 g. of this prepolymer in a dried flask was poured a solution of 9 g. of the amide same as in Example 3 dissolved in 50 ml. of dry dimethyl-formamide, and the mixture was stirred at the room temperature for 2 hours to obtain a viscous solution of block copolymer.

A brown, transparent, tough, elastic film obtained from this block copolymer in the same manner as in Example 1 had the following properties:

=0.69, softening point: 260-280 C. Initial modulus: 42 kg./cm. Strain recovery:

94.6 kg./cm. (at 25 C.) 92.5 kg./cm. (at 70 C.) Tensile stress at 200% elongation:

30 kg./cm. (25 C.) 29 kg./cm. (70 C.) 

